#! /usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

sub Hash_Key_Cap {
        my $entry=shift;

                        %$entry = map { uc $_ => $entry->{$_} } keys %$entry;
        foreach my $main ( sort keys %$entry){
                if( ref $entry->{$main} eq "HASH" ) {
                        %{ $entry->{ $main } } = map { uc $_ => $entry->{ $main }{ $_ } } keys %{ $entry->{ $main } };
                }
                elsif(ref $entry->{$main} eq "ARRAY" ){
                        foreach my $test (@{$entry->{$main}}){
                                if (ref $test eq "HASH")  {
                                        %{$test} = map { uc $_ =>  $test->{ $_ } } keys %{$test} };
                                }
                        }
        }
        return $entry;
}
my %hash=(
                'a'=>'Wow',
                'b'=>['GOOD', 'BAD'],
                'c'=>[ {one=>'perl',
                        two=>'monks',
                        five=>{a=>'b',c=>{ c=>'d' } },
                        three=>'Test',
                        four=>'Best'
                       }, 2],
                'd'=> { five=>5,size=>6}
        );

print Dumper(Hash_Key_Cap(\%hash));